44 
specimens of H. emissarius, apparently belong to that species. These 
specimens have better developed gonads, and they are clearly in 10-13* 
(Pl. II, Fig. 4). One of the specimens has also three pairs of organs that 
are almost certainly degenerating spermathecae. They are in the ante- 
rior parts of 7-9 (Pl. Il, Fig. 4), and open in 6/7-8/9 at the level of 
the lateral line of either side. Since the number and positions of the 
gonads and of the spermathecae in H. emissarius are the same as in H. 
gordioides, the actual status of the former must remain undetermined 
until still more can be learned about the reproductive system. We have 
no information concerning the sperm ducts, oviducts, sperm sacs, or 
ovisacs. These may easily furnish distinctive specific characters. 
A New SPECIES FROM THE ILLINOIS RIVER 
In 1894 and 1895, while in service for the Illinois State Laboratory 
of Natural History at the Biological Station on the Illinois River, the 
writer found many specimens of a Haplotaxis species in the wet banks of 
the river near Havana, Illinois, and preserved a considerable number, 
assuming that they were H. emissarius and that their reproductive organs 
might be sufficiently developed for description. Several series of sec- 
tions were made, but a preliminary study showed that the specimens were 
not sexually mature, and as an anomalous relation of the gonads was 
apparent it seemed advisable to wait for better developed specimens. 
During the interval of over twenty years the desired specimens have not 
been obtained, and a recent study of the material at hand has led to the 
unexpected discovery that the Illinois River worms belong to a species 
-distinct from: H. emissarius. 
HAPLOTAXIS FORBESI, Sp. nov. 
Length, 100-150 mm. Diameter, 0.6-0.7 mm. Somites, 260-284. 
Prostomium approximately twice as long as wide. Setae, two to four 
per somite; dorsal setae much the smaller and limited to a few anterior 
somites. Gizzard in part of 4-5. Nephridia large in 12-14 and posterior 
to 1%. Spermaries: one pair, in 10. Ovaries paired; in 15 and 16. 
Cotypes, in the collection of the Illinois State Laboratory of Natural 
History (Accessions Cat. Nos. 27136 and 27137), and in the collection of 
the writer. Named for Professor S. A. Forbes, who first made known 
the presence of Haplotaxidae in North America. 
But few of the specimens were preserved entire. Only the anterior 
30 or 40 somites were saved in the case of most specimens, since short 
pieces were much more easily prepared for sectioning. Transverse, 
sagittal, and frontal sections of eight anterior ends, and cleared speci- 
mens of nine other anterior ends were used in the study of the more 
important characters. 
EXTERNAL CHARACTERS 
The measurements given above—length, 100-150 mm., and diameter, 
0.6—0.7 mm.—are based on alcoholic material. The number of somites 
* Arabic numerals are used to designate the somites. 
